Re: [Qemu-devel] [PATCH] block: Fix .bdrv_open flags

["Denis V. Lunev" <den@openvz.org>]

On 01/11/2016 09:32 PM, Kevin Wolf wrote:
> bdrv_common_open() modified bs->open_flags after inferring the set of
> options to pass to the driver's .bdrv_open callback. This means that the
> cache options were correctly set in bs->open_flags (and therefore
> correctly displayed in 'info block'), but the image would actually be
> opened with the default cache mode instead.
>
> This patch removes the flags parameter to bdrv_common_open() (except for
> BDRV_O_NO_BACKING it's the same as bs->open_flags anyway, and having two
> names for the same thing is confusing), and moves the assignment of
> open_flags down to immediately before calling into the block drivers. In
> all other places, bs->open_flags is now used consistently.
>
> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
> ---
>   block.c | 13 +++++++------
>   1 file changed, 7 insertions(+), 6 deletions(-)
>
> diff --git a/block.c b/block.c
> index 01655de..ef37d51 100644
> --- a/block.c
> +++ b/block.c
> @@ -905,7 +905,7 @@ static QemuOptsList bdrv_runtime_opts = {
>    * Removes all processed options from *options.
>    */
>   static int bdrv_open_common(BlockDriverState *bs, BdrvChild *file,
> -                            QDict *options, int flags, Error **errp)
> +                            QDict *options, Error **errp)
>   {
>       int ret, open_flags;
>       const char *filename;
> @@ -943,7 +943,8 @@ static int bdrv_open_common(BlockDriverState *bs, BdrvChild *file,
>           goto fail_opts;
>       }
>   
> -    trace_bdrv_open_common(bs, filename ?: "", flags, drv->format_name);
> +    trace_bdrv_open_common(bs, filename ?: "", bs->open_flags,
> +                           drv->format_name);
>   
>       node_name = qemu_opt_get(opts, "node-name");
>       bdrv_assign_node_name(bs, node_name, &local_err);
> @@ -955,8 +956,7 @@ static int bdrv_open_common(BlockDriverState *bs, BdrvChild *file,
>   
>       bs->request_alignment = 512;
>       bs->zero_beyond_eof = true;
> -    open_flags = bdrv_open_flags(bs, flags);
> -    bs->read_only = !(open_flags & BDRV_O_RDWR);
> +    bs->read_only = !(bs->open_flags & BDRV_O_RDWR);
>   
>       if (use_bdrv_whitelist && !bdrv_is_whitelisted(drv, bs->read_only)) {
>           error_setg(errp,
> @@ -969,7 +969,7 @@ static int bdrv_open_common(BlockDriverState *bs, BdrvChild *file,
>       }
>   
>       assert(bs->copy_on_read == 0); /* bdrv_new() and bdrv_close() make it so */
> -    if (flags & BDRV_O_COPY_ON_READ) {
> +    if (bs->open_flags & BDRV_O_COPY_ON_READ) {
>           if (!bs->read_only) {
>               bdrv_enable_copy_on_read(bs);
>           } else {
> @@ -994,6 +994,7 @@ static int bdrv_open_common(BlockDriverState *bs, BdrvChild *file,
>       bdrv_set_enable_write_cache(bs, bs->open_flags & BDRV_O_CACHE_WB);
>   
>       /* Open the image, either directly or using a protocol */
> +    open_flags = bdrv_open_flags(bs, bs->open_flags);
>       if (drv->bdrv_file_open) {
>           assert(file == NULL);
>           assert(!drv->bdrv_needs_filename || filename != NULL);
> @@ -1660,7 +1661,7 @@ static int bdrv_open_inherit(BlockDriverState **pbs, const char *filename,
>       assert(!(flags & BDRV_O_PROTOCOL) || !file);
>   
>       /* Open the image */
> -    ret = bdrv_open_common(bs, file, options, flags, &local_err);
> +    ret = bdrv_open_common(bs, file, options, &local_err);
>       if (ret < 0) {
>           goto fail;
>       }
Reviewed-by: Denis V. Lunev <den@openvz.org>